In order to make aircraft passengers comfortable, and in order to transport them between an airport terminal building and an aircraft in such a way that they are protected from the weather and from other environmental influences, passenger boarding bridges are used which are telescopically extensible and the height of which is adjustable. For instance, an apron drive bridge in present day use includes a plurality of adjustable modules, including: a rotunda, a telescopic tunnel, a bubble section, a cab, and elevating columns with wheel carriage. Other common types of passenger boarding bridges include radial drive bridges and over-the-wing (OTW) bridges. Manual, semi-automated and fully-automated bridge alignment systems are known for adjusting the position of the passenger boarding bridge relative to an aircraft, to compensate for different sized aircraft and to compensate for imprecise parking of aircraft.
A manual bridge alignment system requires that a human operator is present to perform the alignment operation each time an aircraft arrives. Delays occur when the human operator is not standing-by to perform the alignment operation as soon as the aircraft comes to a stop. In addition, human operators are prone to errors that result in the passenger boarding bridge being driven into the aircraft or into a piece of ground service equipment. Such collisions involving the passenger boarding bridge are costly and also result in delays. In order to avoid causing a collision, human operators tend to err on the side of caution and drive the bridge slowly and cautiously.
Semi-automated bridge alignment systems also require a human operator, but the human operator may be present at a remote location and interact with the bridge control system in a tele-robotic manner. One human operator may interact with a plurality of different passenger boarding bridges, thereby reducing the costs associated with training and paying the salaries of human operators. Alternatively, certain movements of the bridge are automated, whilst other movements are performed under the control of the human operator.
Automated bridge alignment systems provide a number of advantages compared to manual and semi-automated systems. For instance, automated bridge alignment systems do not require a human operator, and therefore the costs that are associated with training and paying the salaries of human operators are reduced or eliminated. Furthermore, an automated bridge alignment system is always standing by to control the passenger boarding bridge as soon as an aircraft comes to a stop. Accordingly, delays associated with dispatching a human operator to perform a bridge alignment operation are eliminated, particularly during periods of heavy aircraft travel.
In some instances, it is desirable to align a plurality of passenger boarding bridge tunnel sections with a plurality of different doorways of an aircraft. For instance, a dual boarding bridge includes a front tunnel section for being aligned with a doorway that is forward of the wing of the aircraft and an over-the-wing (OTW) tunnel section for being aligned with a doorway that is above or aft of the wing of the aircraft. Optionally, the front tunnel section is one of an apron drive bridge, a radial drive bridge and a nose-loader bridge. Transferring passengers simultaneously via the front tunnel section and the over-the-wing tunnel section results in shorter aircraft turnaround times, since it is the aircraft doorway that most significantly limits passenger flow. Typically, OTW bridges are used only with narrow body aircraft. However, similar results are obtained with wide body aircraft by aligning a plurality of tunnel sections with a plurality of different doorways that are forward of the wing of the aircraft. In each case, more than one passenger boarding bridge tunnel section is moved from an initial or stowed position to a position in which the tunnel section is aligned with a desired one of the plurality of different doorways of the aircraft.
Not all types of bridge alignment systems are well suited for aligning a plurality of passenger boarding bridge tunnel sections to doorways of an aircraft. In particular, a manual or semi-automated bridge alignment system either requires a plurality of human operators, or a single bridge operator must align each tunnel section in sequence. Of course, salaries and training costs escalate when plural bridge operators are employed. Furthermore, one inexperienced bridge operator may limit the overall efficiency of turning around the aircraft. In addition, it may be quicker to move passengers through only one doorway of the aircraft rather than to wait for a single bridge operator to align several different tunnel sections, one at a time.
Automated bridge alignment systems overcome some of the problems that are associated with manual and semi-automated systems. However, it is very costly to equip each different passenger boarding bridge tunnel section with a separate bridge controller, including the associated sensors, safety equipment, communications equipment, etc. Furthermore, when servicing a plurality of doorways that are forward of the wing of an aircraft, the passenger boarding bridge tunnel sections are close together and the risk of collision is increased. In addition, if one or more of the plurality of passenger boarding bridge tunnel sections is not aligned successfully, then it is necessary to call for a human bridge operator to complete the alignment process. This delay in aligning some of the tunnel sections may cause confusion inside the aircraft, since the flight attendants will realize only at the last minute that some exits are unavailable, and the passengers will require new instructions to either wait for the doorway to open, or to move toward another exit.
It would be advantageous to provide a method for aligning plural passenger boarding bridge tunnel sections with a plurality of doorways of an aircraft, which overcomes at least some of the above-mentioned limitations of the prior art. It would be further advantageous to provide a method that is applicable to operation of dual-bridges or multi-bridges of the over-the-wing type, as well as to operation of a plurality of separate passenger boarding bridges.